Golf putter with lead glass head

ABSTRACT

An improved golf putter is disclosed that is constructed having a head made from a lead glass material containing at least 24% lead oxide in its formulation. The lead glass material formulation is heated to a full melting point of about 2500° F. and maintained at such temperature to remove impurities and bubbles before being reduced to a working temperature range of 1500°-2000° F. While in the working range, the lead glass material is press molded into the desired shape of the putter head or otherwise formed into billets that are milled or machined using conventional glass cutting techniques. Upon formation of the desired shape, the body of the putter head is annealed to remove stress in the lead glass material and thereafter the exterior of the putter head is treated to mechanically strengthen the surface area and prevent chipping of the putter head. The resulting lead glass putter head exhibits a density between about 3.0 to 5.0 grams/cm 3  and a Young&#39;s modulus between about 50 to 70 GPa that cause the putter head to impart high energy transfer to the ball upon impact with minimal vibration of the head for greater feel of the impact and consistency in putting. The lead glass putter head may be formed into a variety of configurations each adapted to affix to a conventional putter shaft.

BACKGROUND OF THE INVENTION

The present invention generally relates to golf club construction and more particularly to an improved golf putter having a ball-striking head formed from a lead glass material that produces high energy transfer to the ball with reduced vibration of the head upon impact for greater feel and consistency in putting.

In the game of golf, there is perhaps no more important aspect than putting, the golfing stroke designed to cause a golf ball to roll on the surface of the green into or near the hole. Because of the significant effect that putting has on a golfer's score, much time and technology has been applied to improving the golfer's ability to propel the ball in the intended direction and over the entire distance to the hole using the golf club commonly called the putter. A significant focus of the technology applied to improve putting performance has been directed at the putter itself and particularly the construction of its ball-striking head affixed at the base end of an elongated shaft that is typically held with both hands of the golfer upon a grip at the opposite end of the shaft. Numerous putter heads have been designed and developed in a variety of shapes and constructions to enhance putting performance by increasing the “feel” that the golfer senses in his or her hands at the moment of impact between the golf ball and the putter head. The characteristic “feel” of the putter or tactile sensation transmitted from the striking face of the putter head along and through the shaft to the hands of the golfer on the grip is generally considered to be the most important factor in providing consistent and reliable distance control in putting. Somewhat like a feedback response at the moment of impact with the ball, the “feel” of the putter head together with its visual appearance are often the most commonly cited bases for improved putting control and accuracy.

In pursuit of optimal “feel” in the putting stroke, putter heads have been constructed of various materials and formed in a wide variety of configurations. Most common materials used in the fabrication of putter heads have included metals of aluminum, steel, brass and most recently titanium, and non-metals such as wood, ceramics, graphite, plastic and other elastomers. Composite materials have also been employed and joined together in putter construction to achieve desired physical characteristics of mass weight distribution, moment of inertia and resiliency, particularly with respect to the striking face of the putter head. Glass has been identified as an optimal putter material because of its appearance, formability and resiliency and while some putter head designs have been successfully developed in forms made in whole or in part from glass materials, they have not been found entirely satisfactory in providing a strong and durable putter with the degree of “feel” that is necessary to enhance putting performance. These prior art glass putter heads have been made predominately from soda-lime glass and/or borasilicate glass and are found to be relatively low in their characteristic mass and somewhat high in the elasticity of their striking surface to achieve optimal “feel” desired by golfers in effecting the putting stroke. Because of the generally positive physical characteristics otherwise exhibited by glass as a putter head material, it is therefore important to devise a new and unique putter head construction made from a glass material that affords significant improvement in performance and “feel” over the prior art putter head designs.

SUMMARY OF THE INVENTION

Accordingly, it is a general purpose and object of the present invention to provide a novel golf putter construction that improves the putting ability of a golfer.

A more particular object of the present invention is to provide an improved golf putter constructed having a novel ball-striking head capable of providing the golfer with an increased “feel” upon striking the ball that enhances the golfer's control of ball travel.

Another object of the present invention is to provide an improved putter head construction made of a glass material that imparts maximum energy transfer to the golf ball at impact with minimal vibration affecting the putter head to produce a greater “feel” response or tactile sensation in the hands of the golfer.

Still another object of the present invention is to provide an improved glass putter head that is attractive in its appearance and easily formed in a variety of configurations that can visually aid the golfer in striking the golf ball in the desired direction of travel.

A still further object of the present invention is to provide a glass putter head that is strong and durable through extended golfing use, economical to manufacture, and easily adapted to a variety of shaft connections.

Briefly, these and other objects of the present invention are accomplished by an improved golf putter constructed having a head made from a lead glass material containing at least 24% lead oxide in its formulation. The lead glass material formulation is heated to a full melting point of about 2500° F. and maintained at such temperature to remove impurities and bubbles before being reduced to a working temperature range of 1500°-2000° F. While in the working range, the lead glass material is press molded into the desired shape of the putter head or otherwise formed into billets that are milled or machined using conventional glass cutting techniques. Upon formation of the desired shape, the body of the putter head is annealed to remove stress in the lead glass material and thereafter the exterior of the putter head is treated to mechanically strengthen the surface area and prevent chipping of the putter head. The resulting lead glass putter head exhibits a density between about 3.0 to 5.0 grams/cm³ and a Young's modulus between about 50 to 70 GPa that cause the putter head to impart high energy transfer to the ball upon impact with minimal vibration of the head for greater feel of the impact and consistency in putting. The lead glass putter head may be formed into a variety of configurations each adapted to affix to a conventional putter shaft.

For a better understanding of these and other aspects of the present invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawings in which like reference numerals and character designate like parts throughout the figures thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

For a fuller understanding of the nature and objects of the present invention, references in the detailed description set forth below shall be made to the accompanying drawings in which:

FIG. 1 is a perspective view of a golf putter having a putter head made in accordance with the present invention with the body of the putter head being constructed in a preferred form for right-handed golfer usage;

FIG. 2 is a top elevational view of the putter head of the present invention shown in FIG. 1;

FIG. 3 is a perspective view of the lower portion of a second golf putter with its putter head constructed according to the present invention in an alternate form preferred for right-handed golfer usage;

FIG. 4 is a top elevational view of the putter head construction shown in FIG. 3;

FIG. 5 is a perspective view in part of a third golf putter with a putter head constructed in accordance with the present invention in a form useable by both right-handed and left-handed golfers; and

FIG. 6 is a top elevational view of the putter head construction shown in FIG. 5.

DETAILED DESCRIPTION OF THE INVENTION

The following is a detailed description of a preferred embodiment of the present invention and the best presently contemplated mode of its production and practice. This description is further made for the purpose of illustrating the general principles of the invention but should not be taken in a limiting sense, the scope of the invention being best determined by reference to appended claims.

Referring now to FIG. 1, a golf putter, generally designated 10, is shown including a shaft member 12 fitted with a grip 13 attached along the upper length of the shaft and a putter head 16, constructed in accordance with the present invention, affixed to the bottom end of the shaft member. The shaft member 12 is a conventional member that is generally cylindrical through its length, but may be tapered slightly and bent at one or more angles along the bottom portion of the shaft to accommodate a proper shaft attachment to the putter head 16 with any offset or dimensional spacing desired between the principal shaft angle and the front face 18 of the putter head. The shaft member 12 is made of any suitable material, such as stainless steel or graphite, and is formed in differing lengths designed to place the attached putter head 16 in proper position to strike the golf ball. The grip 13, secured along the shaft member 12 by conventional means, is typically made of a soft and pliable material suitable for handling, such as leather or rubber, that may be contoured and textured on its surface to allow comfortable placement of the hands of the golfer.

Referring now to FIG. 2 in conjunction with FIG. 1, the body 16 of putter head 14 preferred in the present construction is a modified mallet-head style having a substantially semi-circular profile best seen in the plan view of FIG. 2. Made of a lead glass material described below in greater detail, the body 16 of putter head 14 is integrally formed having a front face 18 diametrically disposed at its forward edge for striking the golf ball. Front face 18 is substantially flat across its ball-striking surface from the end nearest to the attachment of shaft 12, commonly called the “heel” of the putter head 14, to the opposite end from the shaft and its attachment, commonly referred to as the “toe” of the putter head. The length of the front face 18 of putter head 14 from heel to toe is the equivalent diameter of body 16, typically being between about 3-5 inches. The height of the front face 18 is the equivalent thickness of the body 16 of putter head 14 and is typically less than 1½ inches or the approximate diameter of the standard-sized golf ball. The front face 18 of putter head 14 is formed to be substantially square to the remaining body 16 with little or no incline built into the face to promote proper roll and reduce skidding of the golf ball upon impact.

A central cavity 20 having a generally cylindrical shape is formed to extend internally through the body 16 of putter head 14 in a direction substantially perpendicular to the top and bottom surface of the body. The central cavity 20 narrows slightly in its diameter from a maximum circular opening made at the surfaces on both the top and bottom of the body 16 and maintains a slightly reduced diameter through the middle thickness of the body. The surface openings of the central cavity 20 are slightly larger than the standard diameter of the golf ball while the reduced diameter of the cavity in the middle of the body 16 is slightly less than standard golf ball diameter. This configuration and sizing of the central cavity 20 thus permits the body 16 of putter head 14 to engage and hold the golf ball within the cavity upon insertion of the ball from either the top or bottom of the body and particularly allows the golfer to pick-up and retrieve a golf ball from the ground on or around the green surface after putting.

A small circular socket 22 typically drilled into the top surface of the body 16 of putter head 14 is sized and shaped to receive and fit closely the bottom end of shaft member 12 for securing attachment to the putter head. Socket 22 is located near to the heel of putter head 14, as shown in FIGS. 1 and 2, and is formed to a depth within body 16 that allows a sufficient length of the shaft member 12 to be inserted and secured within the socket. The interior of socket 22 and the exterior of the bottom end of shaft member 12 may be similarly treated and applied with a suitable glue or cement formulation that firmly bonds the lead glass material of putter head 14 to the shaft member in order to produce a fixed and substantially permanent attachment between the shaft and putter head.

It should be noted and understood that adjustment of the size, depth and angle of incline of the socket 22 may be made to accommodate any type of shaft member 12 and will be instrumental in establishing a proper position of the body 16 of putter head 14 relative to the shaft that permits placement of the putter head squarely behind the golf ball and substantially flat to the green surface when the putter 10 is held in address position by the golfer. It should be further understood that the location of the socket opening 22 may be adjusted upon the body 16 of putter head 14 to suit the particular configurations of the shaft member 12 and the physical requirements of the golfer, and particularly may be moved from the heel position shown on the embodiment of FIGS. 1 and 2 to the opposite side and thus allow conversion of the putter head 14 for use by left-handed golfers.

Alternate configurations of the lead glass putter head construction according to the present invention are shown in FIGS. 3 and 4 and FIGS. 5 and 6, respectively. In FIGS. 3 and 4, a lead glass putter head 30 is shown with its body 32 having a rounded T-shaped profile that is formed with a pair of circular shaped recesses 34 and 35 provided in a symmetrical fashion, one on each side of the otherwise semi-circular body to the rear of front face 36. In this alternate configuration of putter head 30, the front face 36 of body 32 is similarly square to the profile of the body and substantially flat along its forwardly facing surface as in the case of the front face 18 of putter head 14. Unlike the body 16 of putter head 14, however, on the top surface of body 32 between the recesses 34 and 35, a circular socket 38 is centrally located to engage and secure shaft member 12 therein for either right-handed or left-handed use by the golfer.

In FIGS. 5 and 6, a further alternate lead glass putter head 40 is shown having a form of blade-type body 42 with respective front and back faces 44 and 46 that are each square to the main body and flat across their respective surfaces so that either face can be used to strike the golf ball. In this alternate version of the present putter head invention, a circular socket 48 for attaching shaft member 12 is provided and positioned, like that of the socket 22 on putter head 14, at a location on the top of body 42 near to the “heel” of putter head 40. The socket opening 48 can also be formed in the middle of the body 42, like that of socket 38, to allow a center shaft attachment to putter head 40, as may be desired by the golfer.

The main aspect of the present invention is the integral construction of the putter head, in those of the described forms or other selected configurations, from a lead glass material containing at least 24% lead oxide in its composition. Such a lead glass material, sometimes referred to as “lead crystal”, is most often used in making decorative glass objects due to its high refractive index that promotes sparkling and a relatively soft surface that facilitates its decoration by grinding, cutting or engraving. For just those characteristics that make lead glass ideal for decoration, as well as its further brittle character, lead glass has not heretofore been effectively used and processed in the construction of putter heads.

The lead glass material preferred for use in the present putter head construction is a formulation containing at least 24% lead oxide (PbO) or the equivalent amount of PbO combined with and another heavy-metal oxide, such as that of antimony or barium. A first working formulation of the lead glass material found effective in the present invention is as follows:

-   -   65% de-ionized silica sand;     -   24% PbO; and     -   11% soda ash.         The present formulation of the lead glass material is thoroughly         mixed and then heated to a full melting point of approximately         2500° F. After maintaining the melting point temperature for a         sufficient time to remove impurities and bubbles, the         formulation is reduced to a working temperature range of         1500°-2000° F. While in this working temperature range, the         present formulation of lead glass material is press-molded         directly into the intended shape of the putter head or         alternatively, made into billets that are then milled or         machined into the desired putter head shape preferably using         computer-aided (CAD/CAM) water jet or diamond glass cutting         technologies.

In its completed form, whether produced by press-molding or from a machined billet, the resultant putter head of the present invention undergoes an annealing cycle to remove the stresses created in the lead glass. This process of annealing requires the hot glass material to cool uniformly through the softened glass stage of the material, down to the solid state to allow the glass molecules to align in an orderly fashion. A typical annealing cycle for the lead glass putter head constructed according to the present invention includes the following steps in sequence: lowering the temperature of the putter head to an upper annealing level of 940 to 970° F., this step being permitted to occur rapidly in the case of the press-molded form; gradually reducing the temperature level at the controlled rate of 50° F. per hour to the designated annealing temperature of 900° F.; maintaining the designated annealing temperature of 900° F. for a period of one hour; reducing the temperature level, again at the controlled rate of 50° F., to the designated strain point temperature of 850° F.; and lowering the temperature of the putter head to an ambient level at a more rapid rate of 100 to 150° F. per hour.

After annealing is completed, the lead glass body of the putter head is further processed and submitted to one or more surface treatments intended to strengthen the surface areas of the body and its lead glass material so as to resist chipping of the putter head construction upon impact. Conventional surface treatment methods including fire polishing or thermal toughening and chemical toughening using a standard ion exchange procedure such as a salt bath of SiO₂ or KNO₃ at 420° F. may each be employed or combined to provide the putter head body with a mechanically strengthened lead glass surface with a depth of up to 100 microns.

The resulting putter head construction exhibits an excellent combination of physical characteristics, particularly a relatively high density and relative low Young's modulus (E), which together have been determined to contribute to the optimal performance of the present putter head in producing high energy transfer to the golf ball upon impact with reduced vibration of the head for greater feel and consistency in putting. Young's modulus, also referred to as elastic modulus, is an important material parameter that indicates the ratio of stress to strain of the material under an applied force and is thus measured in units of pressure called Pascals (Pa). The value of the Young's modulus serves as an indication of the elasticity or stiffness characteristic of a material. A higher Young's modulus indicates a more stiff material and a lower E value, more elasticity. For comparative analysis, metals, such as low alloy and stainless steels, have E values near 200 GPa, while glasses, such as soda-lime glass (E=69 GPa) and silica glass (E=94 GPa) have much lower Young modulus values. It should be noted that the vibration experienced by a material structure upon impact is directly proportional to its Young's modulus value, and further in this regard, a dampening of the vibration experienced by a putter head upon impact with a golf ball is an important factor in increasing the golfer's felt response to the putt.

In the resulting putter head made from the first working formulation of lead glass material described above, a density of 3.33 grams/cm³ was measured along with a Young's modulus determined to be 55 giga-Pascals (GPa). These characteristic features of relatively high density and low elastic modulus in the lead glass material of the present putter head construction combine to contribute to an improved striking performance and increased “feel” demonstrated with the present putter head and are deemed instrumental in increasing the felt response upon impact while producing effective energy transfer to the golf ball for improved putting control. It should be understood that the addition of a substantial amount of lead in the form of PbO to a soda lime or borosilicate glass is found to yield a higher density glass material with lower elastic modulus. It should be noted, however, that the resultant effect of these combined features in the lead glass material used in the present putter head construction to increase “feel” and ball-striking control in putting is substantial and unexpected in view of prior art and reported technology.

Additional formulations of the lead glass material examined for the present putter head construction contain increased levels of PbO in the range of 25 to 45% of the composition with minor amounts of barium, less than 2% of the material composition, further added. The resultant effects of these additional formulations were to further increase the density up to about 4.00 grams/cm³ and vary the Young's modulus between 50 and 70 GPa. Except for evidence of increased brittleness in the higher ranges of PbO, a condition relieved by the surface strengthening treatment described above, the additional formulations of the lead glass material indicate substantially the same resultant performance in the present putter head construction, producing high energy transfer to the ball with reduced vibration of the head upon impact for greater feel and consistency in putting.

Therefore, it is apparent that the described invention generally provides an improved golf putter construction that enhances the putting ability of a golfer by increasing the “feel” or immediate feedback experienced by the golfer at the moment of striking the golf ball. More particularly, the present invention provides an improved putter head construction made of a lead glass material that is capable of imparting maximum energy transfer to the golf ball at impact with minimal vibration affecting the striking surface of the putter head to cause a more immediate “feel” or tactile sensation to be experienced by the golfer that enhance his or her ability to control the ball travel when putting. The described putter head made of lead glass material is further attractive in its appearance and can be easily formed in a variety of configurations that can visually aid the golfer in striking the ball in the desired direction of travel. In addition, the present putter head of lead glass material is strong and durable through extended use, economical to manufacture and easily adapted to different shaft connections.

Obviously, other embodiments and modifications of the present invention will readily come to those or ordinary skill in the art having the benefit of the teachings presented in the foregoing description and drawings. Alternate embodiments of different shapes and sizes, as well as substitution of known materials or those materials which may be developed at a future time to perform the same function as the present described embodiment are therefore considered to be part of the present invention. For instance, dye coloring material may be added to the formulations of the lead glass material to provide color shades to the putter head while maintaining its transparent appearance. Accordingly, it is understood that this invention is not limited to the particular embodiment described, but rather is intended to cover modifications within the spirit and scope of the present invention as expressed in the appended claims. 

1. A golf putter device comprising: a shaft; and a putter head adapted for attachment to said shaft, said putter head being constructed in a predetermined form from a lead glass material containing at least 24% lead oxide in composition so that said putter head exhibits a density in the range of about 3.0 to 5.0 grams/cm³ and a Young's modulus in the range of about 50 to 70 GPa.
 2. A golf putter device according to claim 1, wherein the composition of the lead glass material contains lead oxide in the range of 24 to 45%.
 3. A golf putter device according to claim 2, wherein the composition of the lead glass material contains minor amounts of barium.
 4. A golf putter device according to claim 1, wherein the predetermined form of said putter head is constructed having a substantially semi-circular body with a central cavity formed therethrough and sized to engage a golf ball.
 5. A golf putter device according to claim 4, wherein the predetermined form of said putter head is molded.
 6. A golf putter head comprising: a body constructed in a predetermined form having a ball-striking surface, said body being composed of a lead glass material containing at least 24% lead oxide and produced having a density in the range of 3.0 to 5.0 grams/cm³ and a Young's modulus between about 50 to 70 GPa.
 7. A golf putter head according to claim 6, wherein the composition of the lead glass material contains lead oxide in the range of 24 to 45%.
 8. A golf putter head according to claim 7, wherein the composition of the lead glass material contains minor amounts of barium.
 9. A golf putter head according to claim 6, wherein the predetermined form of said putter head body is constructed having a substantially semi-circular profile with a central cavity formed through said body and sized to engage a golf ball.
 10. A golf putter head according to claim 9, wherein the predetermined form of said putter head body is press-molded.
 11. In the construction of a putter head intended for striking a golf ball, the improvement comprising: forming the putter head into a body of a predetermined shape from a lead glass material containing at least 24% lead oxide in composition; annealing the body of the putter head to remove stresses created in the lead glass material during forming; and treating the exterior of the annealed body to strengthen the surface areas of the putter head and resist the chipping thereof.
 12. The improved putter head construction according to claim 11, wherein the putter head body exhibits a density in the range of about 3.0 to 5.0 grams/cm³ and a Young's modulus in the range of about 50 to 70 GPa.
 13. The improved putter head construction according to claim 12, wherein the lead glass material used in forming the putter head body contains lead oxide in the range of 24 to 45% in composition.
 14. The improved putter head construction according to claim 11, wherein said step of forming the putter head body comprises: mixing the lead glass material; heating the lead glass material to the full melting point temperature thereof; maintaining the full melting point temperature for sufficient time to remove impurities and bubbles from the lead glass material; reducing the temperature of the lead glass material into the working range thereof; and press-molding the lead glass material into the predetermined shape.
 15. The improved putter head construction according to claim 14, wherein after reducing the temperature of the lead glass material into the working range, said step of forming the putter head body further comprises: producing billets of the lead glass material; and machining the billets into the predetermined shape of the putter head body. 